Nokia iSkoot 6600 User manual

ISSUE 2 01/2004 COMPANY CONFIDENTIAL 1
Copyright © 2003 Nokia. All Rights Reserved.
Customer Care Solutions
Technical Documentation
6(b) - RF Troubleshooting and
Manual Tuning Guide

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Table of Contents Page No
Introduction ...................................................................................................................5
General troubleshooting ................................................................................................6
RF Key Component Placement .....................................................................................7
Receiver Troubleshooting .............................................................................................9
General Description .................................................................................................... 9
General Instructions for RX Troubleshooting ..........................................................10
Measuring RX I/Q signals using RSSI ...................................................................10
Measuring RX performance using SNR measurement ...........................................11
Measuring the RX module manually using Oscilloscope and Spectrum Analyzer 12
GSM900 ..................................................................................................................12
GSM1800 ................................................................................................................14
GSM1900 ................................................................................................................15
Measurement points in the Receiver ...................................................................... 17
Tuning of the RX Using Phoenix ................................................................................19
RX Channel Select Filter Calibration .......................................................................19
RX Calibration .......................................................................................................... 19
RX Band Filter Response Compensation .................................................................. 22
Transmitter Troubleshooting .......................................................................................25
General Description .................................................................................................. 25
Preparation for Fault Finding ....................................................................................26
Fault-finding chart: TX-BB interface and control signals ......................................28
Fault-finding chart: RF side of transmitter .............................................................29
Transmitter Tuning ......................................................................................................30
Introduction ...............................................................................................................30
TX IQ Tuning ............................................................................................................ 30
TX Power Level Tuning ........................................................................................... 34

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Introduction
This document describes the troubleshooting and RF tuning of Nokia 6600 (NHL-10). In gen-
eral, two types of measurements have to be performed during the troubleshooting and repair
of phones:
• RF measurements shall be done with a spectrum analyzer, either connected directly
to the RF connector of the board (“antenna point”), or used together with a high-fre-
quency probe to measure RF signals at points along the TX or RX chain.
• LF (Low-Frequency) and DC measurements shall be done either with a multimeter, or
with an oscilloscope together with a 10:1 probe.
All tuning must be done with Phoenix Service Software, version A9 2003.15.2.25, or later.
Always make sure that the measurement set-up has been calibrated when measuring RF pa-
rameters at the RF connector. Remember to include the correct losses in the module repair jig
and the connecting cable when realigning the phone.
Most RF semiconductors are static discharge sensitive.ESD protection mustbe taken into
account during repair (ground straps and ESD soldering irons).
Mjølner RF ASIC is moisture sensitive. Therefore, Mjølner RF ASIC must be pre-baked prior
to soldering.
RF calibration done via Phoenix software is temperature sensitive because of calibra-
tion of 26MHz reference oscillator (VCXO). According to the Mjølner specification, ambient
temperature has to be in the range of 22 to 36oC.

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General troubleshooting
Thefirststep offault-findingshouldalways beavisual inspection.Carefullyinspectthe RFarea
using a microscope and look for cracks, solder bridges, dry joints, missing components, com-
ponents that have partially come off and other anomalies. Capacitors can be checked to see
that they are not short-circuited, and inductors that they are not open circuits. Also check that
power supply lines are not short-circuited, i.e. not 0Ωto ground.
Instruments needed for trouble-shooting (minimum requirement):
• Oscilloscope
• Multimeter
• Spectrum analyzer (SA)
Note:
Use an attenuator at the spectrum analyzer input to ensure that the SA will not become damaged by
excessive input power from the phone. Check the spectrum analyzer for maximum allowable input
power.
• Power supply that can deliver at least 2Adc
• Nokia 6600 module jig (also called test jig)
• PC with Phoenix installed
Note:
In this text the following terms are used interchangeably:
GSM900 = EGSM900 = EGSM
GSM1800 = DCS band
GSM1900 = PCS band

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RF Key Component Placement
The following figure shows the key components of the RF section.
Figure 1: RF Key Components
Figure 2: RF Key Components
shows key components of the RF section.
ᵟᶌᶒᶃᶌᶌᵿ
ᵱᶕᶇᶒᶁᶆ
ᵮᶍᶕᶃᶐ
ᵟᶋᶎᶊᶇᶄᶃᶐ
ᵱᵟᵵ
ᵱᵟᵵ
ᵡᶃᶊᶊᶓᶊᵿᶐ
ᵲᶐᵿᶌᶑᶁᶃᶇᶔᶃᶐ
ᵧᵡ
ᵠᵟᵪᵳᵬ
ᵱᵟᵵ
ᵶᵲᵟᵪ
ᵴᵡᵭ
ᵏ
ᵐ
ᵑ
ᵓ
ᵔ
ᵕ
ᵖ
ᵏᵎ
ᵠᶊᶓᶃᶒᶍᶍᶒᶆ
ᵲᶐᵿᶌᶑᶁᶃᶇᶔᶃᶐ
ᵏᵐ
ᵢᶓᵿᶊ
ᵡᶍᶓᶎᶊᶃᶐ
ᵏᵑ
ᵠᶓᶄᶄᶃᶐ
ᵟᶋᶎᶊᶇᶄᶃᶐ
ᵏᵒ
ᵱᵟᵵ
ᵒ
ᵗ
ᵠᶓᶄᶄᶃᶐ
ᵟᶋᶎᶊᶇᶄᶃ ᶐ
ᵏᵏ
ᵣᵋ ᵥᵱ ᵫᵗᵎᵎ
ᵥᵱᵫᵏᵗᵎᵎ
ᵥᵱᵫᵏᵖᵎᵎ
E-GSM900
GSM1800

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Copyright © 2003 Nokia. All Rights Reserved.
Figure 3: RF Key Components

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Receiver Troubleshooting
General Description Figure 4: Receiver Signal Path
The receiver is a direct conversion, triple-band linear receiver. NHL-10 uses Mjølner RFIC with
external VCO.
The received RF signal from the antenna/RF connector goes into the RF antenna switch where
the signal is fed to the E-GSM900, GSM1800 or GSM1900 path. For each band, a RX band-
pass SAW filter with unbalanced input and balanced output follows. All blocks are specified as
50Ωsingle ended, only the SAW filter output to the Mjølner input is differentially matched to
LNA Gopt. The LNAs are integrated in Mjølner and have two gain levels. The first one is max.
gain nominally 12 dB, the second one is about 30 dB below max. gain. The gain selection con-
trol of the LNAs is done via the serial interface.
The differential RX signals are further amplified in the “pre-gain” stage and then mixed down to
baseband inside Mjølner using two Mixers with a 90° phase shift in the LO signal resulting in
an in- and quadrature phase paths. Local oscillator signal is generated with the external VCO.
The VCO signal is buffered and divided by 2 (DCS/PCS) or by 4 (EGSM). Accurate phasing is
generated in LO dividers.
The Rx BB chain incorporates AGC, channel select filter and DC compensation. The AGC is
adjusted in 6 dB steps in Mjølner. The DCN1 gain can be adjusted to +24/+18/+12/+6/0 dB.
Theattenuatorgaincanstepfrom0/-6/-12/-18/-24/-30/-36/-42/-48dB.OtherBBamplifiershave
a nominal summed gain of 58dB. The total dynamic range of AGC alone is 72dB. The 3rd order
active channel filters in Mjølner defines the channel selectivity (flat response up to +/-90kHz
typical). Integrated base band filters are based on active RC filters with on-chip capacitors. The
baseband filters are distributed to following stages: BBAMP1, LPF1, LPF2. DC compensation
is split to DCN1 and DCN2. DCN1 is used to compensate DC offset from RF front-end imper-

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fections. DCN2 centres the differential signal with respect to the common mode reference volt-
age of 1.35V. Differential, filtered I/Q-signals are finally fed to the sigma-delta ADC’s in the
UEM. Further filtering in the digital domain occurs in the sinc decimation filter and DSP based
FIR filters
General Instructions for RX Troubleshooting
Connect the phone to a PCwith DAU-9S cable and dongle and follow the followinginstructions.
Measuring RX I/Q signals using RSSI
• Start Phoenix Service Software and establish a connection to the phone.
• Select File -> Scan Product Ctrl R.
• Wait until the phone software version is shown in the lower part of the screen.
• Select Testing -> RF controls.
• Select Band -> GSM900/GSM1800/GSM1900.
•Active unit -> RX.
•Operation mode -> Burst.
•RX/TX channel -> 37/700/661.
• Select RF Alt-M
Testing -> T
RSSI -> R
The set-up now looks like this:

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• Apply a signal with frequency of:
EGSM: 942.467MHz (channel 37 + 67.710KHz offset),
GSM1800: 1842.867MHz (channel 700 + 67.710KHz offset),
GSM1900: 1960.067MHz (channel 661 + 67.710KHz offset),
and a power level of –80dBm to the RF connector (remember to compensate for the
cable loss).
•InRSSI reading click Read now.
The resulting RSSI level should be –80dBm in each band.
Measuring RX performance using SNR measurement
Note: This measurement also provides an indication of the conducted sensitivity.
• Start Phoenix Service Software and establish a connection to the phone.
• Select File -> Scan Product Ctrl R.
• Wait until the phone software version is shown in the lower part of the screen.
• Select Testing -> RF controls.
• Select Band -> GSM900/GSM1800/GSM1900.
• Active unit -> RX.
• Operation mode -> Burst.
•RX/TX channel -> 37/700/661.
• Select Maintenance Alt-M
Testing -> T
SNR Measurement -> M
• Select Fast SNR.
• Choose the respective band (EGSM900, GSM1800, GSM1900).
• Press Measure.
• Follow the instructions for Signal generator set–up in the pop–up window.
• Press OK.
• Read the SNR result. The SNR should be: EGSM900: > 20dB
GSM1800: > 18dB
GSM1900: > 18dB
• Check the sensitivity value.
The set-up should now look as shown in the following figure. The icon also includes a pop-up
window for reference.

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Measuring the RX module manually using Oscilloscope and Spectrum Analyzer
Spectrum Analyzer level values depend on the probe type and should be validated using a
known good NHL-10 sample. The levels that are given here are measured using a high fre-
quency probe.
Measuring with Oscilloscope on RXINN or RXQINN (J606 –608) and RXID or RXQD (J211 –
J212) is recommended only if RSSI reading does not provide enough information. No dedicat-
ed test points exist for RX I/Q signals, however, they can be accessed by probing on a via hole
plating.
GSM900
• Start Phoenix Service Software and establish a connection to the phone.
• Select File -> Scan Product Ctrl R.
• Wait until the phone software version is shown in the lower part of the screen.
• Select Testing -> RF controls.
• Select Band -> GSM900.
• Active unit -> RX.
• Operation mode -> Continuous.
•RX/TX channel -> 7.
•AGC -> 9.

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The input freq/level of the signal generator is 942.467710MHz, -60dBm.
Figure 5: Fault finding chart for GSM900
Apply -60 dBm
942.4 MHz, offset
67.71 kHz
from generator to
antenna connector
Check RSSI using
Phoenix Does it
match Sig Gen
Output level ?
Is L.O running ?
Check RX/TX
switch at RX 900
Z601
Input -63 dBm
Output -63dbm
Oscilloscope
check Vc1, Vc2,
Vc3 at Z601 signal
0V
Spectrum analyzer
EGSM SAW filter
Z604
output -66 dBm
Spectrum analyzer
Check signal after
inductors L606 and
L607
-66 dBm
Check SAW filter
Z604
Oscilloscope
VRX 2.7 V on
Mjoelner
Check inductors
L606, L607
Check Base band
Check RX/TX
switch
Check Mjoelner
YES
YES
NO
NO NO
NO
NO
NO
YES
YES
EGSM chain
functional
Refer to
Synthesiser Fault -
finding chart
Probe J606 -609
RX I &Q Does
waveform look like
example given
earlier ?
Probe J211 &J212
Is digital data
visable ?
Replace UPP
Replace UEM
YES
YES
NO
YES
YES
NO
NO
visible

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Probed RX I/Q signals J606 - 609 with signal setting to 942.467710MHz, -60dBm. Note that
the display is the same for both GSM1800/1900 bands as well.
• Signal amplitude: 456mV
• DC offset: 1.36V
• Frequency: approx 67KHz
GSM1800
• Start Phoenix Service Software and establish a connection to the phone.
• Select File -> Scan Product Ctrl R.
• Wait until the phone software version is shown in the lower part of the screen.
• Select Testing -> RF controls.
• Select Band -> GSM1800.
•Active unit -> RX.
•Operation mode -> Continuous.
•RX/TX channel -> 700.
•AGC -> 9.
The input freq/level of the signal generator is 1842.867710MHz, -60dBm.

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Figure 6: Fault finding chart for GSM1800
GSM1900
• Start Phoenix Service Software and establish a connection to the phone.
• Select File -> Scan Product Ctrl R.
• Wait until the phone software version is shown in the lower part of the screen.
• Select Testing -> RF controls.
• Select Band -> GSM1900.
•Active unit -> RX.
•Operation mode -> Continuous.
•RX/TX channel -> 661.
•AGC -> 9.
Apply -60 dBm
1842.8 MHz, offset
67.71 kHz
from generator to
antenna connector
Check RSSI using
Phoenix Does it
match Sig Gen
Output level ?
Is L.O running ?
Check RX/TX
switch at RX 1800
Z601
Input -63 dBm
Output -65dBm
Oscilloscope
check Vc1, Vc2,
Vc3 at Z601 signal
0V
Spectrum analyzer
EGSM SAW filter
Z602
output -70 dBm
Spectrum analyzer
Check signal after
inductors L603 and
L604
-73 dBm
Check SAW filter
Z602
Oscilloscope
VRX 2.7 V on
Mjoelner
Check inductors
L603, L604
Check Base band
Check RX/TX
switch
Check Mjoelner
YES
YES
NO
NO NO
NO
NO
NO
YES
YES
EGSM chain
functional
Refer to
Synthesiser Fault -
finding chart
Probe J606 -609
RX I &Q Does
waveform look like
example given
earlier ?
Probe J211 &J212
Is digital data
visable ?
Replace UPP
Replace UEM
YES
YES
NO
YES
YES
NO
NO
visible

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The input freq/level of signal generator is 1960.067710MHz, -60dBm
Figure 7: Fault finding chart for GSM1900
Apply -60 dBm
1960 MHz, offset
67.71 kHz
from generator to
antenna connector
Check RSSI using
Phoenix Does it
match Sig Gen
Output level ?
Is L.O running ?
Check RX/TX
switch at RX 1900
Z601
Input -63 dBm
Output -65 dBm
Oscilloscope
check Vc1, Vc2,
Vc3 at Z601 signal
Vc1, Vc3 =0V
Vc2=2.7V
Spectrum analyzer
EGSM SAW filter
Z603
output -70 dBm
Spectrum analyzer
Check signal after
inductors L608 and
L609
-73 dBm
Check SAW filter
Z603
Oscilloscope
VRX 2.7 V on
Mjoelner
Check inductors
L608, L609
Check Base band
Check RX/TX
switch
Check Mjoelner
YES
YES
NO
NO NO
NO
NO
NO
YES
YES
EGSM chain
functional
Refer to
Synthesiser Fault -
finding chart
Probe J606 -609
RX I &Q Does
waveform look like
example given
earlier ?
Probe J211 &J212
Is digital data
visable ?
Replace UPP
Replace UEM
YES
YES
NO
YES
YES
NO
NO
visible

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Measurement points in the Receiver
Figure 8: Measurement points at the RX SAW filters –Z602, Z603, Z604
Figure 9: Measurement points for I/Q baseband signals

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Figure 10: Measurement points for RX I/Q digital signals
Figure 11: Measurement points at the Antenna switch

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Tuning of the RX Using Phoenix
RX Channel Select Filter Calibration
This calibration is calibrating the Baseband filter inside Mjølner ASIC. It is done by internally
measuring a prototype filter, for this reason the calibration is done once, not separately for all
three bands.
• Select Tuning -> RX Channel Select Filter Calibration.
• Press Tune.
RX channel select filter calibration is finished.
RX Calibration
The RX Calibration is used to determine the gain at different gain settings for the front-end and
the Mjølner ASIC and needs to be done in all three bands.
RX-calibration requires an external signal generator.
• Select Tuning -> RX calibration.
• Select band: GSM900.

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• Press Start.
• Follow the instructions in the pop–up window.
• Press OK.